The CAN bus system is used for the networking of devices for communication, for example, in a vehicle and, because of its parallel topology, it is very well-suited for many other communication applications. The CAN bus system transmits messages using the CAN protocol as described in the CAN specification in ISO 11898.
At present, the use of CAN bus systems is increasingly required, in which a higher clock rate and, for this reason, a higher data transfer rate is possible than in CAN, for example, CAN-HS, CAN-FD, etc. In CAN-HS bus systems (HS=high-speed) a data transfer rate of up to 500 Kbit per second (500 Kbp/s) is possible. In a CAN-FD bus system, a data transfer rate of greater than 1 Mbit per second (1 Mbp/s), 2 Mbp/s, 4 Mbp/s and potentially greater is possible. In CAN-FD, messages are transmitted according to the specification “CAN with Flexible Data Rate, Specification Version 1.0” (source: http://www.semiconductors.bosch.de).
Even though the introduction of CAN-HS and CAN-FD enables the migration of existing control units and vehicle platforms to higher data rates, there is however a problem when a CAN transceiver is to carry out a conventional CAN-HS operation and also a CAN-FD operation.
At present, all parameters of a CAN transceiver are namely fixedly configured. A CAN transceiver is also called a CAN transmitter/receiver unit. The configuration or dimensioning of the CAN transceiver selected at that time has to comply with all specified demands. Apart from a compliance with the functional parameters, such demands are, for example, related to:                emission;        direct power injection (DPI) which is a method for the measurement of interference immunity in the area of electromagnetic compatibility (EMC); and        electrostatic discharge (ESD).        
In CAN bus systems, the signal on the bus includes two signals CAN_H and CAN_L, which are ideally in phase opposition, so that the electrical and magnetic fields of both signal lines cancel each other out. In a test, in which it is checked whether the demands related to direct power injection (DPI) are met, the so-called DPI test, a signal transmitted on the CAN bus may only be shifted by 200 ns.